Incoming Call "Unknown"

Hello. I just got a Droid 2 Global a few days ago, and I'm having trouble with incoming calls. Even if the person is in my contact list, their number shows up as "Unknown." I thought maybe my dad had his number set to "hide caller ID," but I've since gotten a call from someone else, and another from my grandmother - and I know my grandmother doesn't have her caller ID hidden, or even know how to hide it!
Any suggestions on what to do?

All of my contacts have the area code before the number, and it still won't work. People who I don't know/don't have in my contacts also show up "unknown" (won't show a number at all) also. I tried resetting the phone to no avail.

I ended up calling Verizon and they fixed it within a couple of minutes, so it had nothing to do with the phone itself. Just thought I should post this in case someone else had this problem.
Thanks for your help.